1. Field of the Invention
The invention relates to a method of noninvasively testing a donor organ in preparation for transplant. More specifically, the invention is directed to a method for preoperatively testing for the suitability of an organ, such as a liver, and predicting postoperative transplant graft function.
2. Description of the Prior Art
In recent years, the medical field has developed techniques for saving and prolonging life by transplanting an organ, such as a liver into a patient.
The process of harvesting an organ from a donor, preserving the organ in transport, which involves keeping the organ cold, and subsequently transplanting the organ is associated with what is known as "preservation/reperfusion injury" In particular, in the preservation stage of handling an organ, such as a liver, the "injury" is localized in a specific region, mainly, in the cells which line the blood vessels. These cells are known as microvascular endothelial cells. This "injury" is the principal cause of nonfunction of the organ when transplanted into the patient.
In addition to transplanting a liver, other organs include a lung, a heart, and a small intestine. Both experimental and clinical evidence are available for the transplanting of a liver. For the remaining three organs, experimental evidence is available.
In liver transplants, up to 10% of human livers will not function following transplantation. This is referred to as primary nonfunction. If primary nonfunction occurs, the only alternative there is to save the patient's life is to retransplant another liver, which retransplantation operation has a subsequent 50% to 60% mortality rate.
Presently, there are no known tests available to the medical profession which can accurately and in an noninvasive manner predict the severity of "preservation/reperfusion injury" prior to an operation which results in primary nonfunction of the graft, and the degree to which primary nonfunction will occur in the patient.
With regard to the health care system, the need for retransplanting an organ, particularly a liver, due to primary nonfunction increases the cost from a quarter of a million dollars up to approximately two million dollars. This increase in costs is due to two factors; the surgery of the retransplantation itself, and the intensive care unit.
There remains, therefore, a very real and substantial need to predict the extent of injury done to the microvascular endothelial cells during the preservation stage of the organ, and equating this extent of injury with the likelihood and degree of primary nonfunction occurring in the graft of a liver transplant patient.
There remains a further need to devise a method in which the likelihood of initial transplant failure of an organ is substantially decreased or eliminated
For a test to be clinically useful, it should be noninvasive, rapidly performed, and reliable There remains a further need to devise a method for predicting graft organ function postoperatively by performing tests with these characteristics prior to the organ transplant operation.